1. Field of the Invention
The present invention relates to a machine tool that machines a workpiece while moving a vertically set spindle and the workpiece relatively to each other in X-axis, Y-axis, and Z-axis directions.
2. Discussion of the Related Art
For example, a vertical machining center that machines a workpiece using a table movable in X-axis and Y-axis directions and a spindle movable in a Z-axis direction is generally structured, as shown in FIG. 10, to include: a column 61 fixedly disposed on a back end of a fixed bed 60 when seen from a front side of the machine; a saddle 62, for placing a workpiece W thereon, disposed on a front part of the fixed bed 60 to be movable in the Y-axis direction (forward and backward direction); a table 63 disposed on the saddle 62 to be movable in the X-axis direction (right and left direction); and a spindle head 65, with a spindle 64 attached thereto, disposed on a front face of the column 61 to be movable in the Z-axis direction (vertical direction).
In some conventional vertical machining centers of this type, the stroke of the saddle 62 in the Y-axis direction is secured by the structure such that the spindle head 65 is overhung from the column 61 toward the front side by a Y-axis stroke amount.
Further, in some cases, a tool magazine 66 of an automatic tool changer is disposed on a side face of the column 61 for replacing a preceding working tool T attached to the spindle 64 by a subsequent working tool housed in the tool magazine 66.
The above-described vertical machining center can also sometimes include a workpiece changer for replacing a machined workpiece by a subsequent machined workpiece. In this case, the use of a turn-type workpiece changer can shorten the workpiece replacement time. This turn-type workpiece changer is disposed on a front side of the machine (an operator's side).